Note that an exception's properties are populated when the exception is *created*, not when it is thrown. Throwing the exception does not seem to modify them.

Among other things, this means:

* The exception will blame the line that created it, not the line that threw it.

* Unlike in some other languages, rethrowing an exception doesn't muck up the trace.

* A thrown exception and an unthrown one look basically identical. On my machine, the only visible difference is that a thrown exception has an `xdebug_message` property while an unthrown one doesn't. Of course, if you don't have xdebug installed, you won't even get that.

The reason because Exception class does not implement the Throwable interface is Exception exists since PHP5, while Throwable was defined in PHP7! So, Throwable interface is only for core use purpose, you cannot implement it in your own classes, if you want to make your classes "throwable" you have to extend Exception class.